/*
 * ------------------------------------------------------------------------
 *
 *  Copyright by KNIME AG, Zurich, Switzerland
 *  Website: http://www.knime.com; Email: contact@knime.com
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License, Version 3, as
 *  published by the Free Software Foundation.
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 *  This program is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, see <http://www.gnu.org/licenses>.
 *
 *  Additional permission under GNU GPL version 3 section 7:
 *
 *  KNIME interoperates with ECLIPSE solely via ECLIPSE's plug-in APIs.
 *  Hence, KNIME and ECLIPSE are both independent programs and are not
 *  derived from each other. Should, however, the interpretation of the
 *  GNU GPL Version 3 ("License") under any applicable laws result in
 *  KNIME and ECLIPSE being a combined program, KNIME AG herewith grants
 *  you the additional permission to use and propagate KNIME together with
 *  ECLIPSE with only the license terms in place for ECLIPSE applying to
 *  ECLIPSE and the GNU GPL Version 3 applying for KNIME, provided the
 *  license terms of ECLIPSE themselves allow for the respective use and
 *  propagation of ECLIPSE together with KNIME.
 *
 *  Additional permission relating to nodes for KNIME that extend the Node
 *  Extension (and in particular that are based on subclasses of NodeModel,
 *  NodeDialog, and NodeView) and that only interoperate with KNIME through
 *  standard APIs ("Nodes"):
 *  Nodes are deemed to be separate and independent programs and to not be
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 *  License, the License does not apply to Nodes, you are not required to
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 *  may freely choose the license terms applicable to such Node, including
 *  when such Node is propagated with or for interoperation with KNIME.
 * ---------------------------------------------------------------------
 *
 * History
 *   Sep 3, 2019 (bjoern): created
 */
package org.knime.filehandling.core.connections.base.attributes;

import java.nio.file.attribute.BasicFileAttributes;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;

/**
 * Utility class for basic file attributes.
 *
 * @author Bjoern Lohrmann, KNIME GmbH
 * @noreference non-public API
 */
public final class BasicFileAttributesUtil {

    private BasicFileAttributesUtil() {

    }

    /**
     * Parses the given file attribute selector string and creates a map with the selected basic file attributes.
     *
     *
     * @param basicFileAttributes The {@link BasicFileAttributes} to put into a map.
     * @param attributeSelectorString Comma-separated list of basic file attributes "selectors", where a selector is an
     *            attribute name, and may optionally by prefixed with "basic:"). Unknown attributes are ignored.
     * @return a map representation of the selected {@link BasicFileAttributes}.
     */
    public static Map<String, Object> attributesToMap(final BasicFileAttributes basicFileAttributes,
        final String attributeSelectorString) {
        final String[] attributeSelectors = attributeSelectorString.split(":");

        if (Arrays.stream(attributeSelectors).anyMatch((s) -> s.equals("*") || s.equals("basic:*"))) {
            return allAttributesToMap(basicFileAttributes);
        } else {
            return selectedAttributesToMap(basicFileAttributes, attributeSelectors);
        }
    }

    /**
     * Puts all basic file attributes into a map.
     *
     * @param basicFileAttributes The {@link BasicFileAttributes} to put into a map.
     * @return a map representation of the given {@link BasicFileAttributes}.
     */
    private static Map<String, Object> allAttributesToMap(final BasicFileAttributes basicFileAttributes) {
        final Map<String, Object> toReturn = new HashMap<>();
        toReturn.put("lastModifiedTime", basicFileAttributes.lastModifiedTime());
        toReturn.put("lastAccessTime", basicFileAttributes.lastAccessTime());
        toReturn.put("creationTime", basicFileAttributes.creationTime());
        toReturn.put("fileKey", basicFileAttributes.fileKey());
        toReturn.put("isDirectory", basicFileAttributes.isDirectory());
        toReturn.put("isOther", basicFileAttributes.isOther());
        toReturn.put("isRegularFile", basicFileAttributes.isRegularFile());
        toReturn.put("isSymbolicLink", basicFileAttributes.isSymbolicLink());
        toReturn.put("size", basicFileAttributes.size());

        return toReturn;
    }

    /**
     * Puts selected basic file attributes into a map.
     *
     * @param basicFileAttributes The {@link BasicFileAttributes} to put into a map.
     * @param attributeSelectors Specifies which basic file attributes to put into the map (a selector may start with
     *            "basic:")
     * @return a map representation of the selected {@link BasicFileAttributes}.
     */
    private static Map<String, Object> selectedAttributesToMap(final BasicFileAttributes basicFileAttributes,
        final String[] attributeSelectors) {

        final Map<String, Object> toReturn = new HashMap<>();

        for (String selector : attributeSelectors) {

            if (selector.startsWith("basic:")) {
                selector = selector.substring(0, "basic:".length());
            }

            switch (selector) {
                case "creationTime":
                    toReturn.put("creationTime", basicFileAttributes.creationTime());
                    break;
                case "lastAccessTime":
                    toReturn.put("lastAccessTime", basicFileAttributes.lastAccessTime());
                    break;
                case "lastModifiedTime":
                    toReturn.put("lastModifiedTime", basicFileAttributes.lastModifiedTime());
                    break;
                case "isDirectory":
                    toReturn.put("isDirectory", basicFileAttributes.isDirectory());
                    break;
                case "isOther":
                    toReturn.put("isOther", basicFileAttributes.isOther());
                    break;
                case "isRegularFile":
                    toReturn.put("isRegularFile", basicFileAttributes.isRegularFile());
                    break;
                case "isSymbolicLink":
                    toReturn.put("isSymbolicLink", basicFileAttributes.isSymbolicLink());
                    break;
                case "size":
                    toReturn.put("size", basicFileAttributes.size());
                    break;
                case "fileKey":
                    toReturn.put("fileKey", basicFileAttributes.fileKey());
                    break;
                default:
                    // ignore unknown selectors
                    break;
            }
        }

        return toReturn;
    }
}
